Feature request: make heavier non-core dependencies optional-dependencies

[jraygauthier]

This set of tool is particularly useful in CI.

However, in order to reduce image size (or nix closure size), removal of non core heavy dependencies such as matplotlib and python-docx would be quite handy.

Simply using optional dependencies group such as plotting and docx would be just perfect.

In the meantime, I have to patch the pyproject.toml and *.py file to achieve that.

From what I understand, mathplotlib is only required by the html sub-command whereas docx by word sub-command.

A first implementation could be to simply remove the associated command when the optional group is not present.

A more granular solution might be nice to preserve html but without plot when !plotting.